@NetStream 

1. Where is ISP router/modem on that floor plan?

2. Do you plan to have Satellite Deco(s) connected with Ethernet cables to Main Deco, or using WiFi?

3. What is firmware version of Deco X20 and can you return it to retailer if I convince you to?

4. How flexible you are in moving Satellite Deco within Master Bedroom?

5. If you have X20 already, can you measure level if its WiFi signal in places where you plan to put Satellite Deco? If you don't know how, I can explain. This is crucial part of deploying WiFi mesh (of any kind) including Deco (of any model).

Hey  @Alexandre. ,

To answer your questions,

1. At the entry place

2.All decos will be Ethernet backhaulled

3.Not sure about the firmware (haven't bought the units yet), I wanted the x20 so as to get wifi 6 in the living room

4. Satellite deco can be moved in master bedroom 

5. I haven't bought the decos yet, so I don't yet have the wifi speeds

ps: which models would you prefer as satellite decos in each of the places

Thanks 

  @NetStream 

Ethernet backhaul - it is good that I asked. It changes a lot and makes it much easier. 

With WiFi mesh having its units hardwired, choose less powerful (less expensive) hardware and place it in every room. You have the right layout of Deco nodes, and you have the right choice of WiFi 6 capable model. 

Just couple recommendations:

1. For WiFi mesh I strongly recommend consistent Deco hardware which all supports the same WiFi protocols. Because of that, you should have all Deco units from X-series. They don't all have to be X20s, but they should all be from X-series (and not XE-, for example X60, X75 is OK, XE75 is not).

2. X20 is the budget model at an entry price, and it is the right one for your situation. In some regions, TP-Link started to offer even more budget-friendly X10. If they are available in your region (check on Amazon or at TP-Link), you can consider them instead.

3. Another model I would have suggested is Deco X50 or X55. These are mid-range models by performance and price, but check them on Amazon. You might find that X50 or X55 is on sale and actually costs less than equivalent set of X20s. I had this situation once, you never know with Amazon. Check X50 and X55 prices separately. If they are going for the same or very close to X20 price, choose X50 or X55 - same price, better hardware, why not? If price difference is as it should be between budget and mid-range model, X20 will be just fine.

4. Some Deco models are not sold by TP-Link in single units, only in 2- and 3-unit sets. It means, plan in advance how many you would need. Your floor map shows four Deco units, you may need to buy two 2-unit sets. 

5. From the other hand, if you place Master Bedroom Deco unit at the middle of the wall between it and Kids Bedroom, that might be enough to provide coverage for kids room. Then, you are going to save on one Deco unit and will only need 3. Yet, if that does not work, you'll be on the look for add-on unit. 

If you want to take that risk and start with three, but later found you need one more Deco unit, for an add-on unit I would recommend same Deco model you have everywhere else, but if it is not sold in single units - then Deco X50-PoE, which is.

6. Finally, and this I tell to everyone who buys networking gear: get it from the place with simple and long enough return policy. What works for others might not work for you. 2-4 weeks return policy should be enough to figure if Deco mesh you've bought meets your expectations.

  @Alexandre. I kinda feel that covering the entire house with X series seems kinda overkill. I thought using satellite decos of either M4 or M5

NetStream wrote

  @Alexandre. I kinda feel that covering the entire house with X series seems kinda overkill. I thought using satellite decos of either M4 or M5

  @NetStream 

You can. TP-Link promises units from different Deco models will work together. Mixing WiFi5 (M4/M5) and WiFi6 (X20) nodes will have the least of issues comparing to, say, mixing WiFi5 and WiFi7 nodes. You might not notice any issues at all, many people don't.

You asked for opinion. At my house, I would not mix WiFi5 and WiFi6 Deco units in one WiFi mesh, and I do not recommend that to others. But this is just my opinion.